SKU: 44499070246

Holley HP EFI ECU & Harness Kit (HO550-601)

Sale price$2636.55 Regular price$2929.50
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Description

Holley HP EFI ECU & Harness Kit (HO550-601)HO550 601 HP EFI ECU WITH HARNESS Suit GM TPI & Holley Stealth Ram Part Number: HO550 601 Looking for a plug and play alternative for your stock or built late model factory EFI engine? How about a replacement ECU for your older Holley C950? Holley has you covered. HP EFI ECU and harness kits are designed to be used with popular factory EFI engines as an alternative to the factory ECU and harness or as a replacement for your C950 ECU. The HP allows you

HO550-601 - HP EFI ECU WITH HARNESS

Suit GM TPI & Holley Stealth Ram

Part Number: HO550-601

Looking for a plug and play alternative for your stock or built late model factory EFI engine? How about a replacement ECU for your older Holley C950? Holley has you covered. HP EFI ECU and harness kits are designed to be used with popular factory EFI engines as an alternative to the factory ECU and harness or as a replacement for your C950 ECU. The HP allows you to accurately control the fuel and ignition of your engine along with additional controls for nitrous, boost, or water meth.
NEW V2 SOFTWARE FEATURES:
"Quick Start" ignition and fueling strategy for LS x Engines
Data Logger. Scalable axes, Smoothing, Multiple graph view ability, Pre-defined notes fields and many more
Strip Chart Real-Time Data Viewer
Integrated Boost Control - Boost vs Time, Boost vs Gear (Time or RPM), Boost vs RPM, Boost vs Speed, Launch control. Boost launch builder, Over-boost safeties, Boost scramble
Traction Control - Power reduction via timing, nitrous percentage or boost (Requires Davis Technologies Holley Module)
“Quick Start” fueling for all engines
Option for VE based fueling strategy
Fuel Map and Learn Function Smoothing
Configurable User Password Protection
Fully Configurable lap top Gauge Panel
FEATURES:
Optional 5.7” full-color touchscreen LCD allows easy on-the-fly tuning,data-logging or can be used as an easy to see graphical gauge panel
Eight sequentially driven 8:2 peak and hold injector drivers, capable of driving up to 16 low or high impedance injectors as a standard feature. Multiple staged injector strategies
Eight channel Distributorless Ignition (DIS)outputs capable of directly driving “Smart” ignition coils or Holley DIS coils. Will drive 2 wire coils with the addition of PN 554-112 high current coil driver module
Plug and Play control of factory GM 24x and 58x LSx engines
Integrated single channel wide band oxygen sensor control. Works with NTK or Bosch sensors
Internal data-logging standard with a huge 2GB of memory
4 Stage progressive nitrous control
Turbo boost control
Integrated water/methanol injection control
Self-tuning fuel table strategy greatly simplifies tuning process
Individual cylinder fuel and spark control allows you to unlock your engine’s potential
Works with 4, 6, 8 cylinder engines
Unique lb/hr based fueling strategy greatly simplifies and commonizes tuning
Advanced idle, closed loop, and enrichment strategies allow for very stable operation
ECU is fully potted and can be mounted in the engine compartment or interior
Sealed automotive and marine grade connectors
Allows for use of common OEM sensors as well as customer sensor calibration input
Ignition Plug and Play with GM 24x and 58x LSx engines, GM HEI, Ford TFI, magnetic and hall effect trigger, and other ignition systems. New Plug and Play applications in process. Custom settings can be configured to allow many other applications
1-5 Bar MAP sensor capability
Two channel knock control sensor Inputs for both one or two wire knock sensors
Dedicated fuel and oil pressure inputs
Controls both stepper and PWM Idle Air Control (IAC) motors
Speed density, Alpha-N, or combination fueling strategies
4 Programmable high or low Pulse Width Modulated (PWM) outputs and 4 fully configurable inputs can be configured for use
4 Stage nitrous oxide control
Fully featured nitrous control eliminates the need for a separate nitrous controller device
Can be configured “Wet” or “Dry” with closed loop feedback
Progressive control based on time, RPM, or boost, requires part # 554-111
Lean or rich safety cutoff
Full timing retard/control configurability per stage based on RPM or time
Integrated Water/Meth

Shipping Notes
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Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
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SKU: 44499070246

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4.4 ★★★★★
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L. Sun
New York, US
★★★★★ 5
Beautiful brown privacy screen!
Color: Brown, Size: 3 Panel, Color: Brown, Size: 3 Panel
Why did you pick this product vs others?: The measurements were perfect for what I was looking for.  The length and width are the same as my rattan raised garden bed which I have placed in front of the screen on the deck.  This secures the screen so there is no issue of weather conditions. I have been looking for weeks for a privacy screen at every possible product and combination. and almost gave up when I noticed the measurements of the screen would fit behind my raised bed!  Now I am going to plant some flowers in it.  This is a terrific buy for me.  i am so happy! Looks great: The perfect size, color, and design match my brown deck rattan furniture. Ease of assembly: No assembly which is nice in this hot weather! Room divider: It provides much needed privacy
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on July 8, 2025
R
Verified Purchase
Rebecca Kraidy
New York, US
★★★★★ 4
Not my favorite but I dont hate it.
Very solid base pieces but shelves have been on and off falling down. Not the best quality but its Definitely worth the price
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 22, 2026
K
Verified Purchase
kyle
Draper, US
★★★★★ 5
Very nice item
Really love the look of this bookcase and also the sturdiness of it. It’s really heavy and has great shelf space as well as being tall enough that I can use the top for figurine/collectable storage but not so tall that the items on top are unreachable which is nice. It was a little difficult to assemble with my husband getting hurt slightly when putting on the backer boards but once we had extra hands to help it was easy enough to finish up.
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Reviewed in the United States on March 20, 2026
A
Verified Purchase
Ambleside mom
Bozeman, US
★★★★★ 3
has some positives and negatives
The bookcases are very sturdy and look very nice. The instructions are easy to follow and they are good value for money (compared to other prices these days) The negatives are that the back is hard to have on exactly flush as they should be. The back panel is taped together poorly and is the main reason for the panels not lining up. I made it work with some creativity though. My main issue is that one of the main shelves (part 3) had the holes drilled backward and so you had to assemble it with the bare wood facing out. I will paint this to get a close match. You can't replace just one part and I didn't want to return the 80 lb package and go the refund route
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Reviewed in the United States on February 25, 2026
C
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Clemson Z
Omaha, US
★★★★★ 1
poor quality
the middle connection is so weak, resulting separate when moving. so poor quality, not recommended. better to buy Sander etc other brands
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 26, 2026

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